This autoimmune disease is associated with auditory and vestibular symptoms. Incomplete information is available on its manifestations in the auditory system. This investigation studies the auditory system deficits in an attempt to identify the most common sites of lesions and to profile the course of this disease within the auditory system. To date, most patients demonstrate some sensorineural loss, usually without brain stem involvement. Substantial fluctuations in peripheral hearing are being observed. Auditory brain stem response (ABR) evaluations are performed as needed and seem to be a sensitive indicator of retrocochlear vascular damage. Preliminary data show some patients with abnormal ABRs following exacerbation of their illness.